Anti-Backup Suture Anchor

ABSTRACT

Devices and methods are provided herein that generally involve suture anchors having one or more anti-backup features configured to resist or prevent backward movement of a suture that is pulled through the suture anchor. In some embodiments, the suture anchor can be configured to permit a suture to slide freely in one direction but resist or prevent suture movement in the opposite direction. For example, cleats can be rotatably mounted within the suture anchor, can project radially outward from an exterior sidewall of the suture anchor, or can project circumferentially from sidewalls of one or more channels formed in the suture anchor&#39;s exterior surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/623,258, filed Sep. 20, 2012, and entitled “Anti-Backup SutureAnchor,” which is incorporated herein by reference in its entirety

FIELD

The present invention relates generally to devices and methods foranchoring sutures in bone or other bodily tissue.

BACKGROUND

Soft tissues, such as ligaments, tendons, and muscles, are attached to alarge portion of the human skeleton. In particular, many ligaments andtendons are attached to the bones which form joints, such as shoulderand knee joints. A variety of injuries and conditions require attachmentor reattachment of soft tissue to bone. For example, when otherwisehealthy tissue has been torn away from a bone, surgery is often requiredto reattach the tissue to the bone to allow healing and naturalreattachment to occur.

A number of devices and methods have been developed to attach softtissue to bone. These include screws, staples, cement, suture anchors,and sutures alone. Some of the more successful methods involve use of asuture anchor to attach a suture to the bone, and tying the suture in amanner that holds the tissue in close proximity to the bone.

The tissue may be attached to the bone during open surgery, or duringclosed (e.g., arthroscopic) surgical procedures. Closed surgicalprocedures can be preferred since they are less invasive and are lesslikely to cause patient trauma. In a closed surgical procedure, thesurgeon performs diagnostic and therapeutic procedures at the surgicalsite through small incisions, called portals, using instrumentsspecially designed for this purpose. One problem encountered in the lessinvasive, closed surgical procedures is that the surgeon hassignificantly less room to perform the required manipulations at thesurgical site. Thus, devices and methods are needed which will allow asurgeon to effectively and easily attach tissue to bone in the smallspaces provided by less invasive surgical procedures.

Proper attachment of soft tissue requires that it be placed in theanatomically correct position to promote optimal healing. Conventionalmethods for attaching soft tissue to bone have typically used anchorsthrough which sutures can be pulled to draw a piece of soft tissueattached to the suture into proximity of the bone surface after theanchor is inserted in a predrilled bone cavity. Such methods thenrequire the free end or ends of the suture to be tied off to hold thesoft tissue in place. This requires a high degree of dexterity from thesurgeon, and it can be difficult or impossible to maintain ideal tensionon the suture while tying the knot, as there is a tendency for thesuture to slip.

There is thus a need for improved devices and methods for attaching softtissue to bone which reduce the tendency for the suture or anchor topull out of the bone and which allow the suture to be tensioned withoutslipping and without requiring knot tying.

SUMMARY

Devices and methods are provided herein that generally involve sutureanchors having one or more anti-backup features configured to resist orprevent backward movement of a suture that is pulled through the sutureanchor. In some embodiments, the suture anchor can be configured topermit a suture to slide freely in one direction but resist or preventsuture movement in the opposite direction. For example, cleats can berotatably mounted within the suture anchor, can project radially outwardfrom an exterior sidewall of the suture anchor, or can projectcircumferentially from sidewalls of one or more channels formed in thesuture anchor's exterior surface.

In one aspect, a suture anchor is provided that can include an elongatebody having proximal and distal ends, an inner cavity formed therein,and first and second elongate cut-outs formed in opposed sides of theelongate body. The suture anchor can also include a suture-engagingelement disposed within the inner cavity of the elongate body and havinga width that is greater than an outer diameter of the elongate body suchthat opposed terminal ends of the suture-engaging element protruderadially outward through the first and second elongate cut-outs formedin the elongate body. The suture-engaging element can be configured toallow a suture extending around the elongate body and along the cut-outsto slide freely in a first direction, and to engage the suture andprevent sliding movement of the suture in a second, opposite direction.

The suture-engaging element can be retained within the inner cavity ofthe elongate body. The suture-engaging element can be at least one ofrotatable about a fixed axis within the inner cavity of the elongatebody and flexible about a fixed axis within the inner cavity of theelongate body. A first terminal end of the suture-engaging element canbe angled proximally toward the proximal end of the elongate body, and asecond terminal end of the suture-engaging element can be angleddistally toward the distal end of the elongate body. The elongate bodycan be substantially cylindrical. The elongate body can include one ormore bone-engaging features formed on an exterior surface thereof. Thesuture-engaging element can include a central body portion having firstand second arms extending tangentially therefrom in opposite directions.The terminal ends of the first and second arms can include channelsconfigured to receive a suture therein, the channels being definedbetween sharp tips configured to engage bone. The suture-engagingelement can include a central body portion having first and second armsextending therefrom, the first and second arms having respective firstand second elbows formed therein. When the suture anchor is implanted ina bone, tension applied to the suture in the second, opposite directioncan be effective to force the suture-engaging element into engagementwith the bone.

In another aspect, a suture anchor is provided that can include anelongate body having proximal and distal ends and a plurality of surfacefeatures formed on an external surface of the elongate body for engagingbone. The suture anchor can also include first and second series ofcleats aligned longitudinally along first and second opposite sides ofthe elongate body, the first series of cleats being angled proximallytoward the proximal end of the elongate body and the second series ofcleats being angled distally toward the distal end of the elongate body.

The first series of cleats can be configured to prevent a suture fromsliding distally relative thereto while allowing a suture to freelyslide proximally relative thereto, and the second series of cleats canbe configured to prevent a suture from sliding proximally thereto whileallowing a suture to freely slide distally relative thereto. When thesuture anchor is implanted in a bone, tension applied to a suture in afirst direction can be effective to force the first and second series ofcleats into engagement with the bone and tension applied to the suturein a second, opposite direction can be effective to pull the first andsecond series of cleats out of engagement with the bone. The sutureanchor can include a suture-receiving member formed in a distal end ofthe elongate body for receiving a suture therethrough. The elongate bodyand the first and second series of cleats can comprise a unitary member,or the first and second series of cleats can be formed as separateinserts and can be attached to the elongate body.

In another aspect, a method for anchoring tissue to bone is providedthat can include inserting a suture anchor into bone and applyingtension to free ends of a suture coupled to the suture anchor such thatthe suture slides around the suture anchor and pulls soft tissue coupledto a looped end of the suture toward the suture anchor. The sutureanchor can include at least one suture-engaging element that allows thesuture to slide in a first direction relative to the suture anchor, butthat engages and prevents the suture from sliding in a second oppositedirection relative to the suture anchor to thereby lock the suturerelative to the suture anchor and thereby secure the soft tissue to thebone.

The suture-engaging element can include a rotating cleat having opposedterminal ends that extend radially outward from opposed sides of thesuture anchor, wherein the rotating cleat rotates to engage and preventmovement of the suture in the second direction. The suture-engagingelement can include first and second series of cleats formed on anexternal surface of the suture anchor and extending longitudinallytherealong, the first series of cleats being angled proximally toprevent the suture from sliding distally relative thereto, and thesecond series of cleats being angled distally to prevent the suture fromsliding proximally relative thereto. The method can also include forcingthe suture-engaging element into engagement with the bone by releasingtension from the free ends of the suture and allowing the soft tissue toexert a pulling force on the suture in the second opposite direction.

The present invention further provides devices, systems, and methods asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a cross-sectional side view of a bone with soft tissueapproximated thereto using a prior art suture anchor;

FIG. 2 is a cross-sectional perspective view of a bone with an exemplaryembodiment of a suture anchor implanted therein, the suture anchorhaving a rotating suture-engaging element;

FIG. 3 is a cross-sectional side view of the suture anchor of FIG. 2;

FIG. 4 is a perspective view of another exemplary embodiment of asuture-engaging element;

FIG. 5 is a side view of another exemplary embodiment of asuture-engaging element;

FIG. 6 is a cross-sectional perspective view of a bone with an exemplaryembodiment of a suture anchor implanted therein, the suture anchorhaving first and second series of cleats formed on a sidewall of thesuture anchor;

FIG. 7 is a cross-sectional view from a first perspective of a bone withan exemplary embodiment of a suture anchor implanted therein, the sutureanchor having first and second series of cleats disposed in channelsformed in a sidewall of the suture anchor; and

FIG. 8 is a cross-sectional view from a second perspective of the boneand suture anchor of FIG. 7.

DETAILED DESCRIPTION

Devices and methods are provided herein that generally involve sutureanchors having one or more anti-backup features configured to resist orprevent backward movement of a suture that is pulled through the sutureanchor. In some embodiments, the suture anchor can be configured topermit a suture to slide freely in one direction but resist or preventsuture movement in the opposite direction. For example, cleats can berotatably mounted within the suture anchor, can project radially outwardfrom an exterior sidewall of the suture anchor, or can projectcircumferentially from sidewalls of one or more channels formed in thesuture anchor's exterior surface.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

FIG. 1 illustrates a prior art suture anchor 10. In use, the sutureanchor 10 is inserted into a bore hole 12 formed in a bone 14. A lengthof suture 16 is threaded through a piece of soft tissue 18 and the twofree ends 20, 22 of the suture 16 are passed through an aperture 24 inthe suture anchor 10. Tension is applied to the two free ends 20, 22 ofthe suture 16 to approximate the soft tissue 18 to the bone 14. The twofree ends 20, 22 of the suture 16 are then tied together in a knot (notshown) to hold the soft tissue 18 in place adjacent to the bone 14. Asnoted above, it can be difficult and time consuming to tie the sutureends 20, 22 in a knot, particularly during minimally-invasiveprocedures. In addition, the suture 16 tends to slip during theknot-tying operation or after the surgery is completed, making itdifficult to maintain the soft tissue 18 in close approximation to thebone 14 and under appropriate tension.

FIGS. 2 and 3 illustrate an exemplary embodiment of a suture anchor 100that includes a suture-engaging element 102 for resisting or preventingsuture backup. In particular, the suture-engaging element 102 can permita suture 104 to be pulled tightly in a first direction and can preventthe suture 104 from sliding in a second, opposite direction.

The illustrated suture anchor 100 is generally in the form of anelongate body 106 having proximal and distal ends 106 p, 106 d. While asubstantially-cylindrical elongate body 106 is shown, the elongate bodycan also have other shapes, including that of a rectangle or that of acone that tapers from a larger-diameter proximal end to asmaller-diameter distal end.

A head 108 is formed at the proximal end 106 p of the elongate body 106.In some embodiments, the head 108 can be a substantially planar radialflange and can be configured to lie flush or sub-flush with the surfaceof a bone 110 in which the suture anchor 100 is implanted. The sutureanchor can alternatively be headless. The head 108 can also includefirst and second proximal apertures 112, 114 through which the suture104 can be received. In some embodiments, the proximal apertures 112,114 can have a diameter that is at least twice the diameter of thesuture 104 to be secured using the anchor, such that two lengths of thesuture 104 can pass through each aperture 112, 114 at the same time. Thehead 108 can also include any of a variety of driving interfaces, suchas a hexagonal recess 116.

The distal end 106 d of the elongate body 106 can include a pointed orrounded tip 118 to facilitate insertion into a bone opening. The distalend 106 d of the elongate body 106 can also include a distal aperture120 through which the suture 104 can be received. The distal aperture120 can extend through the elongate body 106, transverse to the planesin which the first and second cut-outs 124, 126 lie. Like the proximalapertures 112, 114 discussed above, the distal aperture 120 can have adiameter that is at least twice that of the suture 104 to be securedusing the anchor, such that two lengths of the suture 104 can passthrough the aperture 120 at the same time. While a distal aperture 120is shown and described herein, various other suture-receiving memberscan be used instead or in addition, such as an open-ended slot.

The exterior surface of the elongate body 106 can include one or morebone-engaging features 122 formed thereon, such as a helical thread or aplurality of annular projections. When the anchor 100 is threaded orpress-fit into the bone opening, such features 122 can resist or preventthe anchor 100 from being pulled out of the bone opening in the proximaldirection. The exterior surface of the elongate body 106 can alsoinclude first and second elongate cut-outs 124, 126 through whichportions of the suture-engaging element 102 can pass, as describedbelow. The elongate cut-outs 124, 126 can also act as reliefs orchannels in the exterior sidewall of the suture anchor 100 in which oneor more lengths of the suture 104 can be received. In the illustratedembodiment, the first and second elongate cut-outs 124, 126 are formedin diametrically-opposite sides of the suture anchor 100.

An inner cavity or lumen 128 can be formed within the suture anchor 100for housing the suture-engaging element 102. In the illustratedembodiment, the inner cavity 128 extends laterally through the elongatebody 106 and is opened to the surrounding bone 110 via the first andsecond elongate cut-outs 124, 126. The inner cavity 128 can terminateproximal to the distal aperture 120 or other suture-receiving memberprovided in the distal end of the suture anchor 100.

As shown in FIG. 3, the suture-engaging element 102 can extend acrossthe inner cavity 128 and protrude through the first and second elongatecut-outs 124, 126 to interact with a suture 104. The suture-engagingelement 102 can be configured to allow the suture 104 to be pulled in afirst direction through the suture anchor 100 and to resist or preventthe suture from being pulled in a second opposite direction through thesuture anchor. The suture-engaging element 102 includes a central bodyportion 130 with first and second arms 132, 134 extending laterallytherefrom. The arms can be contoured or tapered such that they convergeto pointed terminal ends 136, 138. The suture-engaging element 102 canbe rotatably mounted within the inner cavity 128 of the suture anchor100. For example, a cross pin 140 can extend through an axial openingformed in the central body portion 130 of the suture-engaging element102 and can extend laterally through the elongate body 106 of the sutureanchor 100, perpendicular to a plane in which the first and secondelongate cut-outs 124, 126 lie. The suture-engaging element 102 can thusbe rotatable about a fixed axis within the cavity 128. In someembodiments, the suture-engaging element 102 can be flexible about afixed axis within the cavity 128, such that the suture-engaging element102 is configured to bend or deflect into engagement or into greaterengagement with a suture when the suture is pulled in a first direction,and to bend or deflect out of engagement or into lesser engagement withthe suture when the suture is pulled in a second, opposite direction. Insuch embodiments, the suture-engaging element 102 can be rotatably ornon-rotatably mounted within the cavity 128. The suture-engaging element102 can optionally be molded into the cavity 128, such that it is formedintegrally with the elongate body 106. The extent to which thesuture-engaging element 102 is permitted to rotate or flex can belimited in some embodiments by the dimensions of the cavity 128. Thesuture-engaging element 102 can be mounted such that the first arm 134is angled proximally toward the proximal end of the suture anchor 100and the second arm 132 is angled distally toward the distal end of thesuture anchor 100.

The suture-engaging element 102 can have a width that is greater thanthe outer diameter of the elongate body 106, such that the opposedterminal ends 136, 138 of the suture-engaging element 102 can protruderadially outward from the elongate body 106 through the first and secondcut-outs 124, 126 and into contact with surrounding bone. The width ofthe suture-engaging element 102 can also be greater than the diameter ofthe bone-engaging features 122 formed on the exterior of the elongatebody 106. In some embodiments, the width of the suture-engaging element102 can be less than the length of the elongate cut-outs 124, 126, suchthat the suture-engaging element 102 is prevented from rotating 360degrees about the cross pin 140.

In use, an incision can be formed in proximity to an area of bone 110 towhich a piece of soft tissue 142 is to be approximated. The sutureanchor 100 can then be passed through the incision, for example via aminimally-invasive surgical access device, and implanted in the bone110. A bore-hole can be drilled in the bone 110 and the suture anchor100 can be threaded or press-fit therein, or the suture anchor 100 canbe self-drilled or self-tapped directly into unprepared bone 110.

The suture anchor 100 can be pre-loaded with the suture 104 before thesuture anchor 100 is implanted in bone. Alternatively, the suture 104can be threaded through the anchor 100 after implantation, for exampleusing a common shuttle maneuver. In either case, as shown in FIG. 2, thetwo free ends 144, 146 of a length of suture 104 can be brought togethersuch that the suture forms an open loop 148. Soft tissue 142 can becaptured in the looped portion 148 of the suture 104 as shown, or thesuture 104 can be threaded through the soft tissue 142, e.g., using asuture needle. The two free ends 144, 146 of the suture 104 can bethreaded through the first proximal aperture 112 in the head 108 of thesuture anchor 100, down along the length of the suture anchor throughthe first elongate cut-out 124, through the distal aperture 120, back upalong the length of the suture anchor through the second elongatecut-out 126, and through the second proximal aperture 114 in the head108. Exemplary techniques for loading a suture anchor with a suture aredisclosed in U.S. application Ser. No. 13/623,290, entitled SUTURELEADER, and filed on Sep. 20, 2012, the entire contents of which areincorporated herein by reference. Further exemplary techniques aredisclosed in U.S. application Ser. No. 13/623,467, entitled SUTURE WITHVARIABLE PICK COUNT, and filed on Sep. 20, 2012, the entire contents ofwhich are incorporated herein by reference.

Once the suture anchor 100 is implanted in bone and the suture 104 isthreaded therethrough, the surgeon can apply tension to the two freeends 144, 146 of the suture. This can cause the suture-engaging element102 to rotate counterclockwise in the illustrated embodiment, such thatthe opposed terminal ends 136, 138 thereof move out of engagement withthe surrounding bone opening and the suture 104 is free to slide pastthe suture-engaging element 102. As the free ends 144, 146 of the sutureare pulled, the suture 104 slides counterclockwise through the sutureanchor 100, drawing the piece of soft tissue 142 at the looped end 148of the suture 104 into approximation with the bone surface 110. Inparticular, the portion of the suture in the first elongate cut-out 124slides distally while the portion of the suture in the second elongatecut-out 126 slides proximally. When tension is released from the twofree ends 144, 146 of the suture 104, the natural tension of the softtissue 142 applies a pulling force to the suture in a clockwisedirection. This can cause the suture-engaging element 102 to rotateclockwise, at which time the opposed terminal ends 136, 138 of thesuture-engaging element 102 bite into the surrounding bone and pinchdown on the suture 104. The force applied to the suture 104 resists orprevents the suture from slipping in the clockwise direction.

It will thus be appreciated that the soft tissue 142 can be quickly andeasily approximated to the bone surface 110, without the need to evertie off the two free ends 144, 146 of the suture 104 in a knot. Afterthe soft tissue 142 is approximated as desired, the two free ends 144,146 of the suture 104 can be trimmed and the incision can be closed. Itwill be further appreciated that tension applied in the clockwisedirection by the soft tissue 142 only causes the suture anchor 100 tobecome more secure in the bone opening, as such tension forces thesuture-engaging element 102 more firmly into engagement with thesurrounding bone 110. The suture anchor 100 thus permits the sutureanti-backup and anchor retention functions to be combined in a singlefeature of the device. In some embodiments, the two free ends 144, 146of the suture can be tied off or secured using a knotting element.

FIG. 4 illustrates another exemplary embodiment of a suture-engagingelement 102′. As shown, the element 102′ includes a central body portion130′ with first and second arms 132′, 134′ extending tangentiallytherefrom in opposite directions. The central body portion 130′ can becylindrical and can include an axial opening for receiving the cross pin140 described above. The opposed-terminal ends 136′, 138′ of the firstand second arms 132′, 134′ can include U-shaped channels 150′ definedbetween sharp tips 152′ configured to cut or bite into surrounding bone.The dimensions of the U-shaped channels 150′ can be selected based onthe size of the suture to be anchored using the suture anchor. In someembodiments, the U-shaped channels 150′ have an area that is less thantwice the cross-sectional area of the suture, such that two lengths ofsuture extending through the U-shaped channel 150′ are pinched when thesuture-engaging element 102′ is driven against adjacent bone. Any of theother suture-engaging elements disclosed herein can also include similarU-shaped channels. The suture-engaging element can also have other tipconfigurations, such as a single point, a plurality of teeth, and soforth. The channels can alternatively be V-shaped, flat-bottomedU-shaped, or a shape that matches or is slightly smaller than the suturecross section.

FIG. 5 illustrates another exemplary embodiment of a suture-engagingelement 102″, in which the first and second arms 132″, 134″ includerespective first and second elbows 154″, 156″ formed therein. Each arm132″, 134″ includes a first portion having parallel sidewalls and asecond portion having angled or tapered sidewalls. In other words, thesuture-engaging element 102″ includes a linear central portion, and twotips that extend at an angle relative to the central portion and thatare angled in opposite directions relative to one another.

While a single suture-engaging element 102 is shown in the illustratedsuture anchor 100, it will be appreciated that the suture anchor canalso include more than one suture-engaging element. For example, aplurality of suture engaging elements can be disposed within theinterior cavity 128 of the suture anchor 100. In some embodiments, eachof the suture-engaging elements can be rotatable about axes that areparallel to one another and each of the suture-engaging elements canpass through the first and second elongate-cut-outs 124, 126 to engagethe same suture. In other embodiments, one or more suture-engagingelements can be rotatable about an axis or axes which are perpendicularto the axis or axes about which one or more other suture-engagingelements rotate. In such embodiments, third and fourth longitudinalcut-outs can be formed in the elongate body 106 offset 90 degrees fromthe first and second longitudinal cut-outs 124, 126, respectively, and asecond suture can be threaded through the suture anchor 100 and engagedby the suture-engaging elements.

FIG. 6 illustrates an exemplary embodiment of a suture anchor 200 thatincludes first and second series of cleats 258, 260 formed thereon thatcan permit a suture 204 to be pulled tightly in a first direction andcan prevent the suture from slipping in a second, opposite direction.The series of cleats 258, 260 on the surface of the suture anchor 200can be provided in place of the first and second elongate cut-outs 124,126 of the suture anchor 100 described above. The illustrated sutureanchor 200 is generally in the form of an elongate body 206 havingproximal and distal ends 206 p, 206 d. While a substantially-cylindricalelongate body 206 is shown, the elongate body 206 can also have othershapes, including that of a rectangle or that of a cone that tapers froma larger-diameter proximal end to a smaller-diameter distal end.

A head 208 is formed at the proximal end 206 p of the elongate body 206.In some embodiments, the head 208 can be a substantially planar radialflange and can be configured to lie flush or sub-flush with the surfaceof a bone 210 in which the suture anchor 200 is implanted. The sutureanchor 200 can alternatively be headless. The head 208 can also includefirst and second proximal apertures 212, 214 through which the suture204 can be received. In some embodiments, the proximal apertures 212,214 can have a diameter that is at least twice the diameter of thesuture 204 to be secured using the anchor, such that two lengths of thesuture 204 can pass through each aperture 212, 214 at the same time. Thehead 208 can also include any of a variety of driving interfaces, suchas a hexagonal recess 216.

The distal end 206 d of the elongate body 206 can include a pointed orrounded tip 218 to facilitate insertion into a bone opening. The distalend 206 d of the elongate body 206 can also include a distal aperture220 through which the suture 204 can be received. The distal aperture220 can extend through the elongate body 206, transverse to the planesin which the first and second series of cleats 258, 260 lie. Like theproximal apertures 212, 214 discussed above, the distal aperture 220 canhave a diameter that is at least twice that of the suture 204 to besecured using the anchor, such that two lengths of the suture 204 canpass through the aperture 220 at the same time. While a distal aperture220 is shown and described herein, various other suture-receivingmembers can be used instead or in addition, such as an open-ended slot.

The exterior surface of the elongate body 206 can include one or morebone-engaging features 222 formed thereon, such as a helical thread or aplurality of annular projections. When the anchor 200 is threaded orpress-fit into the bone opening, such features 224 can resist or preventthe anchor from being pulled out of the bone opening in the proximaldirection. The exterior surface of the elongate body 206 can alsoinclude first and second series of cleats 258, 260 alignedlongitudinally along first and second diametrically-opposite sides ofthe suture anchor 200. Each series of cleats 258, 260 can include one ormore ramped projections 262 extending at an angle from the elongate body206. The first and second series of cleats 258, 260 can be angled inopposite directions (e.g., the first series of cleats 258 can be angledtoward the distal end 206 d of the elongate body 206 while the secondseries of cleats 260 can be angled toward the proximal end 206 p of theelongate body 206). In some embodiments, each series of cleats includesat least 3, 4, 5, 6, or 7 or more cleats. The cleats can be spacedlongitudinally along the elongate body 206 and can extend from theelongate body at any of a variety of angles, e.g., less than about 90degrees, more preferably between about 5 degrees and about 60 degrees,and more preferably between about 10 degrees and about 45 degrees. Insome embodiments, the first and second series of cleats 258, 260 can beformed integrally with the elongate body 206, e.g., by injectionmolding. In other embodiments, the series of cleats 258, 260 can beformed as separate inserts that are attached to the elongate body 206using adhesion, sonic welding, or other known attachment techniques. Theinserts can be formed from the same material as the elongate body 206 orfrom a different material. The width of the cleats can be selected basedon a variety of factors, such as the size of the suture anchor 200 andthe size of the suture with which the anchor 200 is to be used. In someembodiments, the cleats extend widthwise across approximately 30 to 90degrees of the suture anchor's circumference.

In use, an incision can be formed in proximity to an area of bone 210 towhich a piece of soft tissue 242 is to be approximated. The sutureanchor 200 can then be passed through the incision, for example via aminimally-invasive surgical access device, and implanted in the bone210. A bore-hole can be drilled in the bone and the suture anchor 200can be threaded or press-fit therein, or the suture anchor 200 can beself-drilled or self-tapped directly into unprepared bone 210.

The suture anchor 200 can be pre-loaded with a suture 204 before thesuture anchor is implanted in bone. Alternatively, the suture 204 can bethreaded through the anchor 200 after implantation, for example using acommon shuttle maneuver. In either case, as shown in FIG. 6, the twofree ends 244, 246 of a length of suture 204 can be brought togethersuch that the suture forms an open loop 248. Soft tissue 242 can becaptured in the looped portion 248 of the suture 204 as shown, or thesuture can be threaded through the soft tissue, e.g., using a sutureneedle. The two free ends 244, 246 of the suture 204 can be threadedthrough the first proximal aperture 212 in the head 208 of the sutureanchor 200, down along the first series of cleats 258, through thedistal aperture 220, up along the second series of cleats 260, andthrough the second proximal aperture 214 in the head.

Once the suture anchor 200 is implanted in bone 210 and the suture 240is threaded therethrough, the surgeon can apply tension to the two freeends 244, 246 of the suture. This can cause the projections 262 of thefirst and second series of cleats 258, 260 to deflect inwardly towardsthe elongate body 208 of the suture anchor 200 and out of engagementwith surrounding bone, such that the suture 204 is free to slidecounterclockwise. In other words, the suture 204 is free to slidedistally along the smooth ramped surfaces of the first series of cleats258 and proximally along the smooth ramped surfaces of the second seriesof cleats 260. As the free ends 244, 246 of the suture 204 are pulled,the suture slides counterclockwise through the suture anchor 200,drawing the piece of soft tissue 242 at the looped end 248 of the sutureinto approximation with the bone surface 210. When tension is releasedfrom the two free ends 244, 246 of the suture 204, the natural tensionof the soft tissue 242 applies a pulling force to the suture in aclockwise direction. This can cause the sharp ends of the projections262 of the first and second series of cleats 258, 260 to deflectradially-outwards from the elongate body 208 of the suture anchor 200,pinching the suture 204 against the surrounding bone 210 and engagingthe bone. The force applied to the suture 204 resists or prevents thesuture from slipping in the clockwise direction.

It will thus be appreciated that the soft tissue 242 can be quickly andeasily approximated to the bone surface 210, without the need to evertie off the two free ends 244, 246 of the suture 204 in a knot. Afterthe soft tissue 242 is approximated as desired, the two free ends 244,246 of the suture 204 can be trimmed and the incision can be closed. Itwill be further appreciated that tension applied in the clockwisedirection by the soft tissue 242 only causes the suture anchor 200 tobecome more secure in the bone opening, as such tension forces the firstand second series of cleats 258, 260 more firmly into engagement withthe surrounding bone 210. The suture anchor 200 thus permits the sutureanti-backup and anchor retention functions to be combined in a singlefeature of the device. In some embodiments, the two free ends 244, 246of the suture can be tied off or secured using a knotting element.

In addition, the positioning of the series of cleats 258, 260 on theexterior of the suture anchor 200 reserves the interior space of theanchor for the driving interface 216 or for additional suture tunnels.The cleats 258, 260 can also be made larger as they are positioned atthe exterior periphery of the suture anchor 200 where the availablesurface area is at a maximum. This can allow for a larger degree ofcleat excursion, thereby improving the strength and reliability of thesuture anchor 200.

While a single pair of radially-extending cleat sets 258, 260 is shownin the illustrated suture anchor 200, it will be appreciated that thesuture anchor can also include multiple such pairs. For example, thesuture anchor can also include third and fourth series of cleats formedon the elongate body offset 90 degrees from the first and second seriesof cleats 258, 260, respectively, and a second suture can be threadedthrough the suture anchor and engaged by the third and fourth series ofcleats.

FIGS. 7 and 8 illustrate an exemplary embodiment of a suture anchor 300that includes channels 364, 366 formed in the exterior surface thereofwith series of cleats 358, 360 extending circumferentially fromsidewalls of the channels. The series of cleats 358, 360 can permit asuture 304 to be pulled tightly in a first direction and can prevent thesuture from slipping in a second, opposite direction.

The illustrated suture anchor 300 is generally in the form of anelongate body 306 having proximal and distal ends 306 p, 306 d. While asubstantially-cylindrical elongate body 306 is shown, the elongate bodycan also have other shapes, including that of a rectangle or that of acone that tapers from a larger-diameter proximal end to asmaller-diameter distal end.

A head 308 is formed at the proximal end 306 p of the elongate body 306.In some embodiments, the head 308 can be a substantially planar radialflange and can be configured to lie flush or sub-flush with the surfaceof a bone 310 in which the suture anchor 300 is implanted. The sutureanchor 300 can alternatively be headless. The head 308 can also includefirst and second proximal apertures 312, 314 through which the suture304 can be received. In some embodiments, the proximal apertures 312,314 can have a diameter that is at least twice the diameter of thesuture 304 to be secured using the anchor 300, such that two lengths ofthe suture 304 can pass through each aperture 312, 314 at the same time.The head 308 can also include any of a variety of driving interfaces,such as a hexagonal recess 316.

The distal end 306 d of the elongate body 306 can include a pointed orrounded tip 318 to facilitate insertion into a bone opening. The distalend 306 d of the elongate body 306 can also include an open-end slot 320through which the suture 304 can be received. Alternatively, the distalend 306 d of the elongate body 300 can include a distal aperture asshown in the suture anchors 100, 200 described above. The open-end slot320 can be sized to accommodate two lengths of the suture 304 to beanchored using the suture anchor 300.

The exterior surface of the elongate body 306 can include one or morebone-engaging features 322 formed thereon, such as a helical thread or aplurality of annular projections. When the anchor 300 is threaded orpress-fit into the bone opening, such features 322 can resist or preventthe anchor from being pulled out of the bone opening in the proximaldirection. The exterior surface of the elongate body 306 can alsoinclude first and second elongate reliefs or channels 364, 366 in whichone or more lengths of the suture 304 can be received. In theillustrated embodiment, the first and second elongate channels 364, 366are formed in diametrically-opposite sides of the suture anchor 300.

First and second series of cleats 358, 360 can be disposedlongitudinally within the first and second channels 364, 366,respectively. Each series of cleats can include one or more rampedprojections 362 extending at an angle from the channel sidewall, suchthat the cleats extend circumferentially relative to the elongate body306. The first and second series of cleats 358, 360 can be angled inopposite directions (e.g., the first series of cleats 358 can be angledtoward the distal end 306 d of the elongate body 306 while the secondseries of cleats 360 can be angled toward the proximal end 306 p of theelongate body 306). In some embodiments, each series of cleats includesat least 3, 4, 5, 6, or 7 or more cleats. The cleats can extend from onesidewall of the channel towards the opposing sidewall of the channel atany of a variety of angles, e.g., less than about 90 degrees, betweenabout 5 degrees and about 60 degrees, and between about 10 degrees andabout 45 degrees. In some embodiments, the first and second series ofcleats 358, 360 can be formed integrally with the elongate body 306,e.g., by injection molding. In other embodiments, the series of cleats358, 360 can be formed as separate inserts and attached to the elongatebody 306 using adhesion, sonic welding, or other known attachmenttechniques. The inserts can be formed from the same material as theelongate body 306 or from a different material.

In use, an incision can be formed in proximity to an area of bone 310 towhich a piece of soft tissue 342 is to be approximated. The sutureanchor 300 can then be passed through the incision, for example via aminimally-invasive surgical access device, and implanted in the bone310. A bore-hole can be drilled in the bone 310 and the suture anchor300 can be threaded or press-fit therein, or the suture anchor 300 canbe self-drilled or self-tapped directly into unprepared bone 310.

The suture anchor 300 can be pre-loaded with a suture 304 before thesuture anchor is implanted in bone. Alternatively, the suture 304 can bethreaded through the anchor 300 after implantation, for example using acommon shuttle maneuver. In either case, as shown in FIGS. 7 and 8, thetwo free ends 344, 346 of a length of suture 304 can be brought togethersuch that the suture forms an open loop 348. Soft tissue 342 can becaptured in the looped portion 348 of the suture 304 as shown, or thesuture can be threaded through the soft tissue, e.g., using a sutureneedle. The two free ends 344, 346 of the suture 304 can be threadedthrough the first proximal aperture 312 in the head 308 of the sutureanchor 300, down along the first channel 364 and its respective firstseries of cleats 358, through the distal open-end slot 320, up along thesecond channel 366 and its respective second series of cleats 360, andthrough the second proximal aperture 314 in the head.

Once the suture anchor 300 is implanted in bone 310 and the suture 304is threaded therethrough, the surgeon can apply tension to the two freeends 344, 346 of the suture. This can cause the projections of the firstand second series of cleats 358, 360 to deflect inwardly towards thesidewalls of the channels 364, 366, such that the suture 304 is free toslide counterclockwise (as viewed from a perspective to the right ofthat shown in FIG. 7 or to the left of that shown in FIG. 8). In otherwords, the suture 304 is free to slide distally along the smooth rampedsurfaces of the first series of cleats 358 and proximally along thesmooth ramped surfaces of the second series of cleats 360. As the freeends 344, 346 of the suture 304 are pulled, the suture slidescounterclockwise through the suture anchor 300, drawing the piece ofsoft tissue 342 at the looped end 348 of the suture into approximationwith the bone surface 310. When tension is released from the two freeends 344, 346 of the suture 304, the natural tension of the soft tissue342 applies a pulling force to the suture in a clockwise direction (asviewed from a perspective to the right of that shown in FIG. 7 or to theleft of that shown in FIG. 8). This can cause the sharp ends of theprojections of the first and second series of cleats 358, 360 to deflectoutwards from the channel sidewalls and to pinch down on the suture 304.The force applied to the suture 304 resists or prevents the suture fromslipping in the clockwise direction.

It will thus be appreciated that the soft tissue 342 can be quickly andeasily approximated to the bone surface 310, without the need to evertie off the two free ends 344, 346 of the suture 304 in a knot. Afterthe soft tissue 342 is approximated as desired, the two free ends 344,346 of the suture 304 can be trimmed and the incision can be closed.

While a single pair of channels 364, 366 and corresponding cleat sets358, 360 is shown in the illustrated suture anchor 300, it will beappreciated that the suture anchor can also include multiple such pairs.For example, the suture anchor can also include third and fourthchannels, with third and fourth series of cleats, formed on the elongatebody 306 offset 90 degrees from the first and second channels 364, 366,respectively, and a second suture can be threaded through the sutureanchor 300 and engaged by the third and fourth series of cleats.Alternatively, or in addition, more than one series of cleats can beprovided in each individual channel. For example, each channel 364, 366can include a first series of cleats extending from one sidewall of thechannel and a second series of cleats extending from the oppositesidewall of the channel. In such embodiments, the two series of cleatsin each channel can extend in the same direction (i.e., proximally ordistally), such that the suture is free to slide in a first directionacross the smooth ramped surfaces of the cleats. When the suture ispulled in a second opposite direction, however, the suture can bepinched between the sharp tips of the opposing cleats, thereby resistingor preventing the suture from sliding in the second opposite direction.The opposing cleats can be positioned directly opposite one another(i.e., at the same longitudinal position along the suture anchor), orcan be positioned offset from one another such that they are staggeredin an alternating fashion along the length of the suture anchor.

The suture anchors disclosed herein can be formed from any of a varietyof materials. In some embodiments, the suture anchors can be formed froma biocompatible, bioabsorbable material which can reduce immunologicalproblems associated with having a foreign substance within the body overa prolonged period of time. Exemplary materials from which the sutureanchors disclosed herein can be formed include bioabsorbable elastomers,copolymer combinations such as polylactic acid-polyglycolic acid(PLA-PGA), and bioabsorbable polymers such as aliphatic polyesters,poly(amino acids), copoly(ether-esters), polyalkylenes oxalates,polyamides, tyrosine derived polycarbonates, poly(iminocarbonates),polyorthoesters, polyoxaesters, polyamidoesters, polyoxaesterscontaining amine groups, poly(anhydrides), polyphosphazenes,biomolecules (i.e., biopolymers such as collagen, elastin, bioabsorbablestarches, etc.) and blends thereof. In some embodiments, the sutureanchors can be formed from polylactic acid, or a composite blend oftricalcium phosphate and polylactic acid. The suture anchors disclosedherein can also be formed from non-absorbable materials, such aspolysulfone, or metals such as titanium. The suture-engaging element(s)and/or the cleat inserts can be formed from any of the materials listedabove, including titanium.

The suture anchors disclosed herein can be provided in any of a varietyof sizes, depending on patient anatomy, procedure type, suture size, andvarious other parameters which will be readily apparent to one havingordinary skill in the art. In some embodiments, the suture anchorsdisclosed herein can be between about 1 mm and about 12 mm in diameterand between about 2 mm and about 24 mm in length.

In some embodiments, a kit can be provided that includes one or more ofthe suture anchors disclosed herein along with one or more sutures foruse therewith. For example, an exemplary kit can include a plurality ofsuture anchors of varying type and size, such that a surgeon can selectthe appropriate suture anchor for a particular application. The kit canalso include a plurality of sutures of various diameters, lengths,colors, materials, and so forth.

In the present disclosure, like-numbered components of the embodimentsgenerally have similar features, and thus within a particular embodimenteach feature of each like-numbered component is not necessarily fullyelaborated upon. Sizes and shapes of the devices described herein, andthe components thereof, can depend at least on the anatomy of thesubject in which the devices will be used, the size and shape ofcomponents (e.g., sutures) with which the devices will be used, and themethods and procedures in which the devices will be used. The figuresprovided herein are not necessarily to scale. Although the devices andmethods disclosed herein are generally directed to surgical techniques,they can also be used in applications outside of the surgical field.

Although the invention has been described by reference to specificembodiments, it should be understood that numerous changes may be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedescribed embodiments, but that it have the full scope defined by thelanguage of the following claims.

What is claimed is:
 1. A suture anchor, comprising: an elongate bodyhaving proximal and distal ends; a plurality of surface features formedon an external surface of the elongate body for engaging bone; and firstand second series of cleats aligned longitudinally along first andsecond opposite sides of the elongate body, the first series of cleatsbeing angled proximally toward the proximal end of the elongate body andthe second series of cleats being angled distally toward the distal endof the elongate body.
 2. The suture anchor of claim 1, wherein the firstseries of cleats are configured to prevent a suture from slidingdistally relative thereto while allowing a suture to freely slideproximally relative thereto, and the second series of cleats areconfigured to prevent a suture from sliding proximally thereto whileallowing a suture to freely slide distally relative thereto.
 3. Thesuture anchor of claim 2, wherein, when the suture anchor is implantedin a bone, tension applied to a suture in a first direction is effectiveto force the first and second series of cleats into engagement with thebone and tension applied to the suture in a second, opposite directionis effective to pull the first and second series of cleats out ofengagement with the bone.
 4. The suture anchor of claim 1, furthercomprising a suture-receiving member formed in a distal end of theelongate body for receiving a suture therethrough.
 5. The suture anchorof claim 1, wherein elongate body and the first and second series ofcleats comprise a unitary member.
 6. The suture anchor of claim 1,wherein the first and second series of cleats are formed as separateinserts and attached to the elongate body.
 7. A method for anchoringtissue to bone, comprising: inserting a suture anchor into bone;applying tension to free ends of a suture coupled to the suture anchorsuch that the suture slides around the suture anchor and pulls softtissue coupled to a looped end of the suture toward the suture anchor;wherein the suture anchor includes at least one suture-engaging elementthat allows the suture to slide in a first direction relative to thesuture anchor, but that engages and prevents the suture from sliding ina second opposite direction relative to the suture anchor to therebylock the suture relative to the suture anchor and thereby secure thesoft tissue to the bone.
 8. The method of claim 7, wherein thesuture-engaging element comprises a rotating cleat having opposedterminal ends that extend radially outward from opposed sides of thesuture anchor, wherein the rotating cleat rotates to engage and preventmovement of the suture in the second direction.
 9. The method of claim7, wherein the suture-engaging element comprises first and second seriesof cleats formed on an external surface of the suture anchor andextending longitudinally therealong, the first series of cleats beingangled proximally to prevent the suture from sliding distally relativethereto, and the second series of cleats being angled distally toprevent the suture from sliding proximally relative thereto.
 10. Themethod of claim 7, further comprising forcing the suture-engagingelement into engagement with the bone by releasing tension from the freeends of the suture and allowing the soft tissue to exert a pulling forceon the suture in the second opposite direction.